Voltage-regulator for dynamo-electric machines.



G. S. N EELEY.

VOLTAGE REGULATOR FOB. DYNAMO ELEOTRIG MACHINES. APPLICATION FILED NOV.30,1906.

Patented Nov. 24, 1908.

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G. S. N EELEY.

VOLTAGE REGULATOR FOR DYNAMO BLEGTRIG MACHINES. APPLICATION FILED NOV.30,1906.-

IEitented Nov. 24, 1908.

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UNITED srarss a "m A l raiser GEORGE S. NEELEY, OF ST. LO U18, MISSOUR.

Specification of Letters Patent.

Patented Nov. 24:, 1908.

Application filed November 30, 1908. Serial No. 345 790.

'0 all whom it may concern:

Be it known that I, Gnonon S. KEELEY, a citizen of the. United States, residing at St. Louis, Missouri, have invented a certain new and useful improvement in Voltage-Regulators for Dynamo -Electric Machines. of which the following is a full." clear, and exact description, such as will enable others skilled in the art to 'which it appertains to make and use the same, reference being had to the accompanying drawings. forming part of this specifi at-ion, in \vhich.

Figure l is a diagiannnatic view illustrating asystem.involving my improvedautomatic voltage regulator for alternating current generators; and Fig. 2 is a diagranr matic View illustrating a modified form of my improvementin a system where rotary transformers are employed.

This invention relates to new and useful improvements in automatic voltage regulators for alternating current generators, the object being to automatically maintain a constant voltage in the work circuit or system, regardless of the demands for current upon the working dynamo. and especially Wl111 the power factor of the system is lowered on account of the use of induction motors on the system. wherein incandescent lightsare also supplied.

My present invention designed especi- 'allyas an improvement upon the system magnet 7* is at zero.

shown in United States Letters Patent No. 838,800, granted to me December 18. 1906.

I have determined that where the apparatus disclosed in my aforesaid patent is employed in practice in a system where induction motors are used the alternating voltage runs sometimes from 5 to 10% lower than it should he. L believe that the reasons for this are the toiiowing: The magnet 11. in

the accompanying drawings, it will he re'-- called, is operated by the potential oi the alternat ng current. system, while the magnet 7 is operated oy' theintensity of the alter l noting current output, the forces of these two magnets beingopposed to each other.

When the power factor of the system is lowered to such a degree that the current is lagging the electro-n1otive force. to the extent of 90 degrees, the force of magnet 11 is at its maximum value, while the torce of As theit'orce of magnet 11 is exerted to lower the voltage, it will readily 'do so because the opposing force of magnet 7* is withdrawn at the instantthat the force of magnet 11 is at its maximum.

From the above it will he seen that it the regulator was open ting under unity power factor and the current should then he thrown out of phase with the electro-m'otive force so as to lag behind the same, therewould be a shifting in the relative positions of the. parts, to wit, the lowering of the force of magnet T and the increasing of the force of magnet 11 of my regulator. which produces increased excitation of the field ot' the eixciter, which results in an increased potential, which compensates for a low power factor in the system. it will, of course. he understood that the low power factor in the system .is produced by a lag in the phase of the current, and as the magnet 7 at any given instant receives the magnetizing impulse later than the magnetizing impulse given to 11 itwill he obvious that the power thus given the magnet 11 at. an earlier instant acts to increase the regulating resistance in the exciter field. order to better explain the condition which my present additionto my former system is intended to improve. where a lower power factor exists. It; is not uncommon to find alternating current s 'stems with a power factor of 5 where the angle ot lag between the current and the electro-nmtive force is only about. if degrees. The effect on the voltage by the use oi the regulating system tional to the power factor. and increases as the power factor recedes from unity.

Where a low power factor exists, that i where the current lags behind the voltage o the system. such a condition demands eonsiderahi more exciting current to keep up tlu- 'altcrnatii'ig voltage to normal. As applicantsmagiietic control close in h based diii'ereint where the apparatus a means must v input (excitan inc output. and

g p-on the regulating resistance. is ore of shunting oit this: era QXilililg current during the oi said former he prin'ii'fled tor inc ing current) fasior E without let it p tent No. $258,800 is which results in .c i i 1!")11'1- tire output -2 seen that when the 4 1 have exaggerated the causes in disclosed in my aforesaid patent is proporexciter.

periods of low power factor so that it will not re-act on the regulating resistance,

which is the gist of this present invention.

Applicants present improvement does not involve any means for causing the voltage and current of an alternating current system ,to keep in phase; but it does involve means for increasing the excitation to keep up the normal oltage in the system regardless of how much current may be lagging behind the voltage oi. the system.

Magnet 11* is in the form of a solenoid magnet whose core forms part of a connecting medium between the spring ll and the ari'nature (3. This magnet is in the circuit of the secondary winding whose primary is across the lighting .or work circuit. Magnet 7" is also in the form of a solenoid magnet whose core is around the connecting medium between the spring 11 and armature 6, and this magnet is energized by' the intensity of the current supplied to the system or such part of it as it may be found necessary to use. A current transformer 23 is employed to energize the magnet 7 The advantages of my improved system are many, chief among which may be mentioned the fact that the controlling elements are operated almost wholly by electro-mag- .netism which render the system very positive and sensitive in its action, causing the deliverance of a very steady voltage on the supply Wires. without the use of dash pots. There is no sparking at the contact points, and hence there is no need for condensers anddiiferential windings on the magnets for the purpose of suppressing arcing at the contacts.

In the accompanying drawings, A is an alternating current generator and B is its 1 and 2 are the primary mains exteY ding from the generator A, and I is an induction motor deriving current from the mains 1 and 2. 3 is the field coil, of said generator. 4 is the field winding of the exciter B. The arrow heads indicate the direction in which the exciter field current travels. Starting from the" positive brush P of the exciter, the field current passes through the winding of ma et 5 thence to the pivoted armature 6. art of the current passes across the contacts 7 and 8, the former of which is carried by the pivoted armature,

while the latter is a fixed adjustable contact,

and the rest of the current passes through the resistances 9, preferably in the form, of specially made incandescent lamps with a negative temperature coefficient, the two parts of the field current then joining and flowing through the field winding 4, thence to the negative brush N of the exciter, thus completing the field circuit.

Armature 6 is pivoted at 10 and-is influenced in one, direction by the spring 11 tends to open the gap between said contacts T and 8. The influence of magnet?) is aug- "mented by the magnetic effort of the pole face 12, which attracts the iron keeper 7 1 mounted on the mo able armature 6. Contact 8 is stationarily-mounted, but adjustablm iu the stationary support 14. A contact-carrying screw 15 is held normally in position by the jam nut 16.

The tension of spring 11 is made adjustable by the screw 17 and the jam nut 18 working in a stationary support 19. ll is a magnet energized by the intensity'of the work circuit for assisting the action of the spring 1 1.

hen the contact 7 is in its extreme position away from the contact 8, the greatest resistance that can be oifered to the field current is set up in the field circuit of the exciter; and if the contact 7 should impinge against the stationary contact 8 the field cir cuit of the exciter would then contain no effective regulating resistance at all. All intermediate positions of the contact 7 be tween these extreme positions automatically create a proportional. and effective regulating resistance in the form of an arc in the field circuit of the exciter, the value of which is varied when a change of current output occurs by changing the strength of the forces which actvupon the armature 6. p

The above described parts are similar to those shown and described in my aforesaid patent No. 838,800, and in operation, if we assume for the moment that all of the current passing from the positive brush of the exciter passes through the winding of magnet 5, and thence to the pivoted armature 6, it will be seen that, depending upon the strength of the magnet 5 tending to pull the armature 6 in one direction to separate contacts 7 and 8, in opposition to the tension of the spring 1r, tending to pull said armature in the opposite direction, to close said contacts, the current will be divided, part of it passing through the contacts 7 and 8 and part through the resistance 9, depending upon which path offers the least resistance. In this manner the gap between the contacts 7 and 8 constit gt'es an automatic variable resistance in th field circuit of the eXciter,. v

around which tie field current of said field the means for regulating the field resistance of the exciter consists of a variable resistance in series with the field of thgexciter, which resistance 1s controlled. by 'dlfieren- .tial forces resulting from placing the intensity of the field current of the emitter in opstationary support 1e.

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position to a m gnet ene gized by the intensity of the current, on rat of the machine and as a. yieldin ,neclianical force, and supplying .a shui'it resistance 9 having a negative temperature coetlicient to relieve said variahle resistance.

My present invention contempla the employment or means for automatically maintaining a constant voltage in the work circuit or svsten'i regardless of the condition or demands for current upon the working dynamo where the power factor is below unity on account of a mixed load of incandescent lights and induction n'iotors: and c'c'nsi. is essentially of a shorts'circuiting device, which, in addition to its slmrtcircuiting capacity. also provides a shunt circuit having a variable resistai'zce around the magnet 5, whereby the pull of said magnet 5 may he kept constant irrespective of the strength of the field current ot the exciter B.

The short-circuiting device in my present construction consists of the following:- A magnet 5 is across the secondary winding of a potential transformer 20. the. primary of which is acrossthe mains 1 and 2. At tention is, directed to the fact that the magnet 5'is influenced by the intensity of the exciter field cnrrentpwhile the magnet 5 is influenced 'hy the voltage across the mains l and 2. ll lagnet exerts a pull upon an armature t3 carrying a movable contact 7 which cooperates with adjustable fixed contact 8, the latter heing mounted upon a it spring 11 mount ed in t 'onary support W and whose tension i djustahle, connected to the armature and tends to close contacts 7 and 8 while the magnet i tends to open said contacts. The contact point 8 may he adjusted hjvflpro *iding meanssimilar to those heretoforedescrihed in connection with the contact 8, and the tension of spring 11 may he adpisted in a guano-er similar to the adustment ot the spring it heretoforedescribed.

Wires 7? co the r agnet 5 and c determined minimlnn flow is thus automat- 1 ically diverted or shunted around the magnet 5 by the action of a magnet 5 working against the tension of the spring ll:

Assuming that the generator A. and exciter B are running a t; "1( eration of ahcvc dc lows: The tension of s .z' s is as tol- 1 adjusted 3 ances. we will say, at 100 volts, across the secondary terminals of the potential transformer 20, the voltage of the alternating mains 1 and 2 will be accurately maintained, as. long as there is no change in the power factor of the system or the current output, because the continual re-action hetween the cxciter field current. traversing the winding of the magnet 5, tends to increase the resistance to its own flow. while the pull of magnet 7" assisted by the tension of spring 11 tends to decrease said resistance.

The voltage of the alternating mains 1 and 2 now being such as to give 100 volts at the nccessar 1 terminals of the potential transformer 20, the tension of spring 11 is adjusted until some in the field current traversing the winding of magnet 5 is on the pointof being diverted or shunted through the Dy-pass wires 5 and 51 and the contacts 7 and 8.

-As the generator A and excite!- B are running atnormal speed and the system has been adjusted to given normal of 100 volts at the secondary terminals of the transformer 20, and, on account at an induction motor load, the power factor of the system' is suddenlyvlowered t0,say 7 0%, during this condition the apparent current output is not equal to the current input (current input inthis instance meaning the field current of the excitcr, which bears a definite relation to the alternator field current) thus the pull of magnet 5 would exceed the pull of magnet 7" (due to the alternating current lagging behind the alternating current vol tag-e, producing etfccts'iu magnets 11 and 7 and on account of this excess pull of the magnet over the magnet 7 the voltage across the mains l and 2 would he lowered (because the pull of magnet 5 alwaysincreases with the exciter field current, tending to increase the resistance across the coutacts 7 and 8), it it were not for the fact that. as the alternating voltage drops, the pull of magnet is proportionately wealo cued. The spring 11 then acts to short-citcuit the winding of magnet 5 by closing the gap between the contacts 7 and R. thus diverting the cXcitcr ticld current from the magnet until the distance l)0l\\0(l] the contacts 7 and S is such that the field excitation raised to the point where normal voltage on the mains] and f2 again restored. At this 3 oin't the force of magnet 13 is equal to the tension of the spring li and any further short circuiiing action is instantly stopped when normal voltage has been re.-

stored. Hence. it will be seen that during 3 the e th 1011 of i i 5 speed the opt normal voltage and unitv 1\-' --n A 1 7V1 1 some ractoi magnet .r and allied apparatus iesipractically dormant, hecausc magnet 5 and magnet 7 are doing practically all the regulating so long as the power factor of the ios system remains 100% or unity. Therefore, magnet 5 and kindred apparatus is of no use except in cases where a low power factor obtains. For the sake of illustration we will assume that during the condition of low power factor it takes of an ampere of current in the exciter field winding 4 to excite up to the normal alternating current voltage, and, further, that g ampere is flowing through the winding of magnet 5 and the remaining 1 ampere is flowing through the by-pass wires 5 and 5 and the contacts 7 and 8*. Should there be another increase in the current output in the mains 1 and 2 the field excitation until normal voltage is restored in the primary mains 1 and '2. \Vhen normal voltage is restored, magnet 5 has the power to prevent the voltage from rising above normal by partly or entirely re.- mOving the short circuit from around the magnet 5 by widening the gap between the contacts T and 8 This action increases the pull of magnet 5, and the gap between the contacts 7 and 8 begins to increase due to the increasing pull of magnet Hence all abnormal movement of the contact 7 is instantly checked because the resistance 9 becomes more and more effective as the gap widens, when all of the-parts will assume their normal steady condition as before. The field current of the exciter may now be ampercs but i=1- ampere will be diverted through the wires 5 and 5 and contacts 7 and 8, while the original 1;} ampere will still fiow in the winding of magnet 5. cans-.

ingits force or pull to be exactly what it was initially. The reverse action takes place when the load or current output is decreased on the mains 1 and Under these condi tions ot'decreasing load or current. output the potential across the mains 1 and :2 will momentarily exceed normal. which results in magnet 5* acting to separate the contacts 7 and 8, which would cause'the full intensity of the exciter field current to be passed through the winding of magnet 5.

Magnet 5 will separate contacts 7 and 8 and the resistances 9 will be instantly made tully effective in the field circuit of the exciter. These conditions tcndl to instantly reduce the field current of the exciter. and of course f the voltage of the alternating"current generator will be correspondingly reduced until normal voltage on the mains 1 and 2 is again reached, at which point the tension of spring l1 equals the pull of magnet 5*, at which time the short-circuiting action of the contacts 7 a and 8 becomes etfective.

From the above it will be seen that as soon as normal voltage has been disturbed, either by a decreasing or an increasing power factor, either the action of spring 11 or magnet 5 predominates and becomes ett'ective. causing more or less of the exciter field current to be passed through the winding of magnet 5 or diverted through the wires 5 and 5 and contacts 7 and 8 In Fig. 2, I have illustrated diagrammatically my improvement wherein a plurality of alternating current generators A .are supplying current in common to a plurality of rotary converters C and C.' The cxciter B supplies exciting current in common to the generators A. The rheostat R- is for the purpose of initially adjusting the resistance in the field winding 3 equal to that of the field winding 3", so that each generator 'will deliver its pro rata of the total current to the rotary transformers C and C.

The regulating system shown in Fig. 2 is similar to that shown in Fig. 1 except that a magnet 22, deriving its energy from the series transformer '23, is employed to automatically supplement the action of the spring 11 in proportion to the current output. sity of the current output of the machine. The object of this is to increase the voltage across the mains l and 2 to compensate for line losses. The results obtained from the magnetizing cfi'ect of the current upon the mains and 2 is the same as if the tension of the spring 11 was manually increased proportional to the increase of current output, which action. as before explained, increases the alternating current voltage; and, like wise. the action is the same as it the tension of the spring ll was manually decreased proportional to the load decrease. By the use of magnet 22. in Fig. 2, the action is absolutcly accurate and automatic for all extrelnc and intermediate conditions of load It might be well to lll (l'(.2ll-'l ()l' tltt'il'oillfl. state that magnet 22 is a. solenoid magnet whose corc forms part of a connecting medium between the spring 11 and thearmature (3 llaving thus described the invention, what Magnet 22 is operated from the inten-' is claimcd as new and desired to be secured by Letters latentis:

1. The improvement in the art of regulating an alternating current generator, the field of which is energized by an exciton-the same comprising means for regulating the field resistance of the exciter in response to differential electro-magnetic forces resulting from placingthe intensity of the field cutcease? erator, the field of which is energized by an exciter, comprising a variable rc istmicc in series with the field of the exciter, and means for controlling the said ,variablc lt*Sl.-';tilHCQ in response to differential elcctro-nnignctic forces resulting from placing the intensity of the field current of the exciter in opposition to the intensity of the current output of the generator, supplying a shunt resistance having a negative temperature coetlicient to relieve said resistance, and means for varyingcthe force derived from the intensity of the field current of the exciter when the power fflCCOlf' of thealternating current sys tem recedes from unity substantially as described.

3. The improvement in the art of regulating an altern iting current generator, the field of which is energized by an excitcr, compris ing means to r regulating the field resistance of the exciter in response to diiierential'electic-magnetic forces resulting from placing the intensity of the field current of the exciter in opposition to the intensity of the current output of the generator, and supplementary means whereby the voltage of the current. output: of the said alternating current generator magnetically regulates the action of the elcctromiagnetic force derived from the tit) field current of the excite! by varying 5 id force when the power factor decreases; substantially as described.

4. The improvement in the art of regiilating the field of an alternating current generator, the held of which is energized by an cxciter, comprising a variable resistance in the field circuit of the exciter, means for controlling the c li'ectiveness of thesaid variable resistance by differential clcctro magnetic forces resulting trom' placing the intensity of the tlcld current of the cxciter in opposition to the intensity of the currcnt output of the generator, supplcincntary electro-inecha ical'maus whereby the voltage of the ratrmnhoutput ot' the said alternating cur- .rcnt generator is made to magnetically regulate the magnct'r action obtained from the intensity of the field current ot-the exciter by varying the torcc derived from the intensity of the current of the cxcitcr on a dccreasing power factor, and shunt. resistances having negative tclnpe 'aturc coctiiciencies to relieve the said variable resistance; substantially as descril'ied.

5. The combination of an alternator, an excitcr thcrct'or, means for regulating the ticld resistance of the cxciter in response to difiireutial elcctro-magnctic forces resulting I from placing the intensity of the lield current ot the tXCllGl in opposition to the intensity of the current output of the generator,

and means for varying the force derived from the intensity of the field current of the exciter proportional to the voltage of said alternator; substantially as described,

6. The combination of anvalternator and its exciter, a variable resistance in series with the field at the exciter, said resistance being responsive to the action of two magnets, one being in circuit with the cXciter field and the other being energized' by the work circuit, means for causing the magnet in circuit with the emitter field to short-circuited, and electro-niagnetic means energized by the voltage of the alternator for opposing said last-mentioned means, and rendering the same ineffective; substantially as described.

7. The combination with means tor regulatingthe resistance of the field circuit of the excite r of an alternating current generator, said means including a magnet in sc ries with the field of the exciter, of a shunt containing a variable resistance around said magnet, and electro-magnetic means for varying said last-mentioned resistance, said means being energized both by the current and by. the voltage of the work circuit of the system substantially as described.

8. The combination with means for regu lating the resistance in the field circuit of the exciter of an alternating current generator, said means including a magnet in series with the field of the eXciter, of a shunt conthining a variable resistance around said magnet, a magnet energized by the intensity of the work circuit for decreasing said va- "riable resistance. and an opposing magnct energized by the voltage of the worlt circuit for increasing said variable resistance; substantially as described.

5). The improvement in the art of regulating the voltage of a plurality of electric gcnerators that are supplying current in common to rotary-transtormcr mains, comprising, in combimition, a single cxciter t'or simultaneously. exciting the fields of all the generators, a regulating resistance and a regulator having dil'icrential magnet coils for controlling the said regulating resistance. one of the said magnets being energized by the exciter-field current, and the other ntag net being energized by the current output of the said generators, and means torvarying the efl cctivencss of one of said diti'crcntial coils, whereby the generator voltage is maintained at normal regardless of what the power factor of the system may be:. substantially as described.

10. in a system of automatic voltage regulation for alternating current generators, the

. generators and their exciter, said generators controlling said variable resis of the said magnet when the voltage of the t generator falls below normal on account of low power factor; substantially as described.

11. The combination of a plurality of electric generators for supplying current. to a common rotary transformer main, :1 single cxciter for supplying all of the fields of said generators, at regulating resistance in the field of said single excitcr, diti'erential coils for controlling said regulating resistance, and means deriving energy from said common main for varying the cti'ectivencss otg one of said diiferential coils; substantially as described. I

12. The combination with rotary trans, former mainline wires, of a plurality of electric generators for supplying current thereto, separately excited fields for said; generators, means for regulating the fieldi resistance of the exciter in response to differential forces resulting from placing the intensity of the field current of the exciter in opposition to the intensity of thecurrent output of said generators, and means for varying the force derived from the intensity of the field current of the exciter; substantially as described. 7

The combination with a plurality of electric generators whose fields are energized by an exciter, said generators supplying the same rotary transformer mains in common, a variable resistance in series with the field of the exciter, said resistance being responsive to the action of two magnets, one in circuit with the exciter field and the other of which is energized by the work circuit, and ditierential coils atfeeted respectively by current and voltage fluctuations of the work circuit for controlling the magnet in circuit with the exciter field; substantially as described. 1

14. The combination with a plurality of supplying a common rotary-transformer main, a variable resistance in series with the field of the exciter, said resistance being responsive to the action of two magnets, one in circuit with the exciter field, and the other of which is energized by .the work circuit, and means for causing the magnet in circuit with the exciter field to be shortkircuited, and electro-magnetic means energized by the voltage of the generator for renderin said last-mentioned means inettectivc; substantially as described. p

-15. The combination with a plurality of electric generators for supplying current in common to a rotary-t "dtlSfOl'll'lBI main line, an'exciter for said generators, a. variable resistance inthe field ('lt'cttlli'fif said eXciter, a shunt for said variable resistance means for tance, said means comprising a magnet in the field circuit of the exciter, said magnet when enerso ace? sistance, means opposing said magnet tending to decrease said variable resistance, and means-deriving energy from the main line for varying the power of said magnet; substantially as described.

16. The combination of a dynamo electric machine, a voltage-controlling circuit there for, a magnet and an automatic variable resi tance in series with said voltage-controlling circuit. an opposing magnet in series with the work circuit of the said dynamo electric machine. means for short-circuiting the winding of said first-mentioned magnet, and means deriving energy from the voltage of the work circuit for rendering said lastmentioned means ineffective; substantially as described.

17. The combination of a plurality of electric generators, a voltage-controlling circuit common to all of the said generators, a

magnet and a regulating resistance in said common voltage-controlling circuit, said magnet being arranged to increase the regulating resistance, an opposing magnet ener gized by the current output of the' said generators, said opposing magnet being arranged to decrease the said re ulating resistance, a' third magnet energized b the voltage of the said generators for assisting the first mentioned magnet, and auxiliary means for periodically short-circuiting the winding of the first mentioned'magnet; substantiallyas described. 18. The combination of an alternator, an exciter therefor, a regulator for controlling, the current output of the exciter, comprising two main differential magnets, one'of said magnets and a variable resistance being in series with the field of the exciter, the other main magnet being in series with the work circuit of said alternatoryand auxiliary means energized by the work circuit for short circuiting the winding of the firstinentioned magnet during periods of low power factor; substantially as described.

19. A regulator fora dynamo, having a regulating resistance, two main controlling .magnets, one of which is in circuitwith the regulating resistance, and the other one in series withthe work circuit of the s stem, and supplementary meansenergized y the voltage of the work circuit for rendering all of the energy of the first mentioned main magnet efi'ective during periods of normal power factor; substantial y as described.

20. Thecombination of'a re ulator for a dynamo, having a main regu ating resist anc, two main difierential coils for operat-" ing said regulating resistance, one of which is responsive to the current through the regulatingresistance, and the other is responsive to the current output of the said dynagized tending to increase said variable rethe action of the first mentioned differential GDP .2 101m fi r 3 x v 1. Ji.. 3 0 1 1t :UH 0

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